Original Research
Morphological Characteristics of the Spinous Process of Axis: Clinical Implications for Cervical Spine Manipulation

https://doi.org/10.1016/j.jmpt.2018.05.002Get rights and content

Abstract

Objective

The purpose of this study was to evaluate the osseous variation of the axis spinous process as it may relate to palpation by clinicians.

Methods

Morphologies of the bifid spinous process in the intact dry axis of 121 Chinese adult were investigated and classified. The angular deflection of the spinous processes, the bifid spinous processes (the bifid portions of the spinous processes), and the length of the bifid spinous processes were observed and measured.

Results

The bifid spinous process morphologies were classified into 4 types: inverted-V shape (n = 49), inverted-U shape (n = 50), M shape (n = 18), and nonbifid spinous processes (n = 4). The direction of the spinous processes and bifid spinous processes were consistent because they depended on each other’s direction of deviation. When the correlation between angular deflection of spinous processes and bifid spinous processes was analyzed, the right deviations of spinous process specimens (29 cases) showed that angular deflections of spinous processes were equal to bifid spinous processes and there was no statistically significant difference seen between them (t = 0.286, P > .05), whereas in the left deviations of spinous process specimens (49 cases), the angular deflection of spinous processes were not equal in length, but bigger than the bifid spinous processes, which was statistically significant (t = -3.079, P = .003 < .05).

Conclusion

The anatomical structure of the spinous processes and the bifid spinous processes vary from one another, but they exhibit some regularity. In clinical spinal manipulation practice, the anatomical characteristic of the axis should be taken into account during cervical static palpation, diagnostic imaging, and treatment.

Introduction

The cervical spinous process and transverse process, which are the vital osseous marks of the cervical static palpation, play important roles in cervical spinal manipulation.1 In clinical spinal manipulation practice, the deviation of spinous process is regarded as very important objective evidence of minor misalignments of joints, such as the type I and II atlantoaxial rotatory subluxation and atlantoaxial rotatory fixations.2 The diseases of the atlantoaxial joint have been a topic of general interest in clinical research owing to the high risk of myelopathy and life-threatening neurologic injuries.3, 4 Cervical spinal manipulation is one of the nonsurgical treatments to treat the diseases of minor misalignments of joints by manual therapists, chiropractors, physical therapists, etc.5, 6, 7 The function of cervical spinal manipulation to correct the atlantoaxial joint is regarded as manipulative reduction.8, 9, 10 In clinical practice, the deviation of spinous processes, which is manually palpable by therapist, is often used to determine atlantoaxial joint derangement.11, 12, 13 However, the structure and function of atlantoaxial vertebral anatomy are quite complex, which results in misdiagnosis and confusion in clinical practice and interventions.14, 15 To improve the accuracy in treatment of minor misalignments of joints, a comprehensive research study has been performed on the anatomical structure of axis to delineate and provide the anatomical basis for accurate positioning of the cervical static palpation.

Section snippets

Participants

The Department of Anatomy, School of Basic Medical Science, Southern Medical University, China, provided 134 dry adult axes specimens of Chinese origin for this study. Of these 134, only 121 of them were included in this study because the rest were either damaged or had transverse processes, which were asymmetrical. The information about age and sex of those axes was unknown. Ethical approval to undertake this study was obtained from Southern Medical University’s Human Research Ethics Committee.

Structures of Bifid Spinous Processes Types

The bifid spinous process morphologies of 121 specimens (117 cases [96.68%] of bifid spinous processes and 4 cases [3.32%] had no bifurcation, as given in Fig 2) were classified into 4 types: inverted-V shape (n = 49), inverted-U shape (n = 50), M shape (n = 18), and nonbifid spinous processes (n = 4) (Fig 3). Forty-three cases (36%) had no deviation of spinous processes including all nonbifid spinous processes, whereas 78 cases (64%) showed some deviation of a type. The average length of 2

Discussion

Previous published studies hardly reported the details related to research on axis spinous processes.1, 16, 17 The axis spinous process is one of the osseous marks of the cervical static palpation in cervical spinal manipulations.1 In the cervical spinal manipulation, the practice of cervical rotation is often performed to correct the deviation of spinous processes, which are regarded as the manipulative reduction.1 In clinical practice, it is important to judge the direction of deviation of

Conclusion

According to the findings of this study, the direction of the spinous processes and bifid spinous processes were consistent because they depend on each other’s direction of deviation; in the right deviation of spinous process specimens, the angular deflection of spinous processes was equal to bifid spinous processes; in the left deviation of spinous process specimens, the angular deflection of spinous processes was not equal to the bifid spinous processes, and in fact, was bigger than the

Funding Sources and Conflicts of Interest

No funding sources or conflicts of interest were reported for this study.

Practical Applications

  • According to the findings of this study, the direction of the spinous processes and bifid spinous processes were consistent because they depend on each other’s direction of deviation.

  • In the right deviation of spinous process specimens, the angular deflection of spinous processes was equal to bifid spinous processes; in the left deviation of spinous process specimens, the angular deflection of spinous

Contributorship Information

  • Concept development (provided idea for the research): Y-K.L.

  • Design (planned the methods to generate the results): L-Q.L.

  • Supervision (provided oversight, responsible for organization and implementation, writing of the manuscript): L-Q.L.

  • Data collection/processing (responsible for experiments, patient management, organization, or reporting data): J.Q.

  • Analysis/interpretation (responsible for statistical analysis, evaluation, and presentation of the results): L-Q.L.

  • Literature search (performed the

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